1 files changed, 117 insertions, 0 deletions
diff --git a/browser/base/content/test/general/browser_windowopen_reflows.js b/browser/base/content/test/general/browser_windowopen_reflows.js
new file mode 100644
index 000000000..7dac8aad6
--- /dev/null
+++ b/browser/base/content/test/general/browser_windowopen_reflows.js
@@ -0,0 +1,117 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const EXPECTED_REFLOWS = [
+  // handleEvent flushes layout to get the tabstrip width after a resize.
+  "handleEvent@chrome://browser/content/tabbrowser.xml|",
+
+  // Loading a tab causes a reflow.
+  "loadTabs@chrome://browser/content/tabbrowser.xml|" +
+    "loadOneOrMoreURIs@chrome://browser/content/browser.js|" +
+    "gBrowserInit._delayedStartup@chrome://browser/content/browser.js|",
+
+  // Selecting the address bar causes a reflow.
+  "select@chrome://global/content/bindings/textbox.xml|" +
+    "focusAndSelectUrlBar@chrome://browser/content/browser.js|" +
+    "gBrowserInit._delayedStartup@chrome://browser/content/browser.js|",
+
+  // Focusing the content area causes a reflow.
+  "gBrowserInit._delayedStartup@chrome://browser/content/browser.js|",
+
+  // Sometimes sessionstore collects data during this test, which causes a sync reflow
+  // (https://bugzilla.mozilla.org/show_bug.cgi?id=892154 will fix this)
+  "ssi_getWindowDimension@resource:///modules/sessionstore/SessionStore.jsm",
+];
+
+if (Services.appinfo.OS == "WINNT" || Services.appinfo.OS == "Darwin") {
+  // TabsInTitlebar._update causes a reflow on OS X and Windows trying to do calculations
+  // since layout info is already dirty. This doesn't seem to happen before
+  // MozAfterPaint on Linux.
+  EXPECTED_REFLOWS.push("TabsInTitlebar._update/rect@chrome://browser/content/browser-tabsintitlebar.js|" +
+                          "TabsInTitlebar._update@chrome://browser/content/browser-tabsintitlebar.js|" +
+                          "updateAppearance@chrome://browser/content/browser-tabsintitlebar.js|" +
+                          "handleEvent@chrome://browser/content/tabbrowser.xml|");
+}
+
+if (Services.appinfo.OS == "Darwin") {
+  // _onOverflow causes a reflow getting widths.
+  EXPECTED_REFLOWS.push("OverflowableToolbar.prototype._onOverflow@resource:///modules/CustomizableUI.jsm|" +
+                        "OverflowableToolbar.prototype.init@resource:///modules/CustomizableUI.jsm|" +
+                        "OverflowableToolbar.prototype.observe@resource:///modules/CustomizableUI.jsm|" +
+                        "gBrowserInit._delayedStartup@chrome://browser/content/browser.js|");
+  // Same as above since in packaged builds there are no function names and the resource URI includes "app"
+  EXPECTED_REFLOWS.push("@resource://app/modules/CustomizableUI.jsm|" +
+                          "@resource://app/modules/CustomizableUI.jsm|" +
+                          "@resource://app/modules/CustomizableUI.jsm|" +
+                          "gBrowserInit._delayedStartup@chrome://browser/content/browser.js|");
+}
+
+/*
+ * This test ensures that there are no unexpected
+ * uninterruptible reflows when opening new windows.
+ */
+function test() {
+  waitForExplicitFinish();
+
+  // Add a reflow observer and open a new window
+  let win = OpenBrowserWindow();
+  let docShell = win.QueryInterface(Ci.nsIInterfaceRequestor)
+                    .getInterface(Ci.nsIWebNavigation)
+                    .QueryInterface(Ci.nsIDocShell);
+  docShell.addWeakReflowObserver(observer);
+
+  // Wait until the mozafterpaint event occurs.
+  waitForMozAfterPaint(win, function paintListener() {
+    // Remove reflow observer and clean up.
+    docShell.removeWeakReflowObserver(observer);
+    win.close();
+
+    finish();
+  });
+}
+
+var observer = {
+  reflow: function (start, end) {
+    // Gather information about the current code path.
+    let stack = new Error().stack;
+    let path = stack.split("\n").slice(1).map(line => {
+      return line.replace(/:\d+:\d+$/, "");
+    }).join("|");
+    let pathWithLineNumbers = (new Error().stack).split("\n").slice(1).join("|");
+
+    // Stack trace is empty. Reflow was triggered by native code.
+    if (path === "") {
+      return;
+    }
+
+    // Check if this is an expected reflow.
+    for (let expectedStack of EXPECTED_REFLOWS) {
+      if (path.startsWith(expectedStack) ||
+          // Accept an empty function name for gBrowserInit._delayedStartup or TabsInTitlebar._update to workaround bug 906578.
+          path.startsWith(expectedStack.replace(/(^|\|)(gBrowserInit\._delayedStartup|TabsInTitlebar\._update)@/, "$1@"))) {
+        ok(true, "expected uninterruptible reflow '" + expectedStack + "'");
+        return;
+      }
+    }
+
+    ok(false, "unexpected uninterruptible reflow '" + pathWithLineNumbers + "'");
+  },
+
+  reflowInterruptible: function (start, end) {
+    // We're not interested in interruptible reflows.
+  },
+
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsIReflowObserver,
+                                         Ci.nsISupportsWeakReference])
+};
+
+function waitForMozAfterPaint(win, callback) {
+  win.addEventListener("MozAfterPaint", function onEnd(event) {
+    if (event.target != win)
+      return;
+    win.removeEventListener("MozAfterPaint", onEnd);
+    executeSoon(callback);
+  });
+}